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[KD0VE]

Still learning about antennas.  Question follows about a noise issue.

21.352MHz .  Rural QTH; typical low ambient noise.   Hexbeam at 40' pointed NE to Europe; EFHW 10-40 oriented N/S  inv V with apex at 30'. EFHW feedpoint about 15' from the house, hexbeam about 50' away.

Easy copy on hexbeam with S1 noise.  On EFHW also good copy (not as good as the hex of course) but there was a nasty, high pitched, continuous and LOUD whine.  I could tune it out with the notch filter but I'm wondering what was a likely source.

thx to anyone offering insight into this.

[WA3SKN]

Noise source... your house!  The local noise source is inside your house.  Now try locate and fix it.
A directional antenna and portable receiver is needed.
What frequency(s) will determine the antenna needed.  Where and when do you hear the noise?

-Mike.

[KD0VE]

Mike; thx for reply.  noise was noticed at 21.352MHz.   present 21.349 - 21.353.9               

[AI5BC]

As stated, you are the source of the noise. Find it and eliminate it.

Completely disconnect your radio from all power and grounding connections. Get a small 12-volt battery to power your radio up on RX. Now turn every breaker in your house off, and your noise should be gone proving you are the source. Now turn one breaker at a time until you hear the noise. Bingo, you found it. Now find what is connected to the branch circuit with the offending equipment plugged into it. Either fix it or get rid of it.

My guess is you are in a ground loop. Did you place a rod outside the shack? Disconnect all your equipment from it and see what happens to the noise.

[KD0VE]

will do breaker isolation test.  Ground loop unlikely, ground rod outside shack tied to service ground, tower ground also tied to service ground.

[AE0Q]

On EFHW also good copy (not as good as the hex of course) but there was a nasty, high pitched, continuous and LOUD whine.  I could tune it out with the notch filter but I'm wondering what was a likely source.

There will probably always be _some_ noise from stuff in the house.  Putting a good CMC along the coax near the house, and another on the coax 6 ft (0.05 WL on lowest band) from the 1:49 xfmr will help keep noise from traveling along the coax to be picked up by the EFHW wire antenna.

[AI5BC]

will do breaker isolation test.  Ground loop unlikely, ground rod outside shack tied to service ground, tower ground also tied to service ground.

You are positively in a ground loop. No way around it. You are in between two grounds.

[K6AER]

Ninety five percent of man made noise is vertical polarized. Tied to a ground.

An EFHW even when strung horizontal is still a vertical antenna.

The HEX beam is a balanced antenna along with a dipole, beam, loop or any other antenna not dependent on a ground plane.

[W1VT]

Another method of noise mitigation is to install the EFHW far from the house with effective common mode suppression on the long feedline.
House noises typically fall off quickly with distance.  Moving the feedpoint of the EFHW antenna 50 or 100 ft from the house should result in a noticeable reduction in noise pickup.

[KD0VE]

thx everyone.  easy enough to move the EFHW 100' away and see what happens but it'll have to wait.  knee deep or worse snow so outside activity curtailed for a while.

I do not understand the "You are positively in a ground loop. No way around it. You are in between two grounds."

[WA3SKN]

21.352 MHz.  A three ft circumference wire loop (and rotatable) will do to get some bearings on the noise.
With portable radio go to the four corners of the house (outside) or yard and try to get some bearings on the noise.  Also powering down the breakers in the house can help locate/isolate the noise.  It takes time but is worth it.  Good luck with the project!

-Mike.

[VR2AX]

No specific idea but I have all my ham life lived with noise of one sort or another.

Most noise as we have to live with tends to cover areas of the frequency bands. Rather than single frequencies or channels. Have you checked harmonic frequencies (10.676, 7.117, VHF etc) for any source.

The EFHW could just be better at receiving on that frequency.

[VE7RF]

will do breaker isolation test.  Ground loop unlikely, ground rod outside shack tied to service ground, tower ground also tied to service ground.

You are positively in a ground loop. No way around it. You are in between two grounds.

My 3/4" main copper water pipe from the water meter (30' from the house) broke years ago.  Replaced with 1" plastic PEX pipe. There went my ground to the main 200 amp panel.    I have 3 x 8' copper ground rods, jackhammered into the ground for the tower (tops are below ground a few inches) in backyard, 10' from the house.  2 ga, stranded, and insulated  RW-90 cadwelded from each grnd rod..... to tower legs, where compression lugs used etc.    Then a bare 2 ga stranded copper wire, buried 6" into the ground, runs from tower, down the side of the house, and terminates on a 4th grnd rod, just outside basement. A single 2 ga, staranded and insulated  RW-90 run from 4th grnd rod to inside of basement, that terminates on a  large rectangular, 1/4" thick aluminum plate.  Then ran a 2 ga rw-90, from alum plate...over to 200 amp panel grnd.  Is this acceptable ??   All the radio gear gets bonded to the same alum plate.

Before, when the  3/4" copper water line was intact, I was probably in a ground loop.

[N4UFO]

Before, when the  3/4" copper water line was intact, I was probably in a ground loop.

How about the fact that your shack is connected to the ground rod outside through the coax AND to the electrical wiring through a three prong plug? Isn't that two paths? 

I have often thought, 'Why ground coax outside shack when it's already grounded through the wiring?' But I am no expert on any of this. I just know I have visited another hams shack that had 'extra grounding' that caused a lightning strike to run through his house taking out appliances on it's way to the mains. I'm not sure anyone is an expert on grounding in reality though... just folks that think they are.  I just follow the idea that with grounding, often 'less is more'. 

BTW, for NOISE problems, I am a big believer in common mode chokes... coax wrapped through a toroid to be specific. Used to have them on all leads in & out of a remote coax switch as well as at the antenna feedpoints. Because one antenna can pickup noise and have it travel to another antenna through the coax shield, then come right into the shack on the center conductor of connected antenna, even though it was an UN-connected antenna that was actually picking up the noise. Added all those chokes (ten total) things got a WHOLE lot quieter. - As always... your mileage may vary.

As for this particular noise, however it is getting to your receiver front end, best to track it down and kill it! 

[W3SLK]

N4UFO said:

How about the fact that your shack is connected to the ground rod outside through the coax AND to the electrical wiring through a three prong plug? Isn't that two paths?

One of the things the XYL got me for Christmas was Ward Silver, N0AX's book  "Grounding and Bonding for the Radio Amateur." Although I didn't get to that section yet, I looked ahead to see if I could find an explanation for you question. Due to publication rights, I can't spell out verbatim but in his 'AC Safety vs. Lightning Protection', (pp 4.12), he says not to rely on one for the other. However, if they are bonded together at the ground rods, they can provide equal protection. He then references NEC Article 810.21  regarding the conductor size for point-to-point grounding. I just breezed through one section where there is an illustration that shows a 'grounding perimeter' where a multitude of ground rods are used. I can't find exactly where it is stated but the idea is not to mitigate current from a lightning strike but to manage it by making more paths available. I would reccommend reading NEC 810 along with his book to make heads and tails out of everything.